1. Field of the Invention
The present general inventive concept relates to a power supply apparatus, and more particularly, to a power supply apparatus with low power in a standby mode.
2. Description of the Related Art
In order to reduce the sizes and heat generation of power supply apparatuses and economize on energy of systems, it is absolutely necessary for the power supply apparatuses to convert power at high efficiency. In particular, zero-voltage switching (ZVS) or zero-current switching (ZCS) is enabled using resonant converters with various shapes to minimize heat generation and power consumption of switch devices, so that power supply apparatuses can operate very efficiently at a rated load or higher.
In most resonant converters, as a primary-side circulating current increases, it causes more conduction loss, thereby degrading the efficiency of the resonant converters. Accordingly, it is more desirable to boost an input voltage. Therefore, in order to use a resonant converter in a place with a low input voltage of about 110V, it is necessary to boost the input voltage using a voltage controller, such as a boost-type active power factor correction (PFC) or a voltage multiplier. However, the boosting of the input voltage may result in the reduction of power efficiency in a standby mode. This is because power loss in the standby mode is mainly caused by switching loss, which is proportional to the square of the input voltage.
Therefore, developing a new technique for minimizing power consumption even in the standby mode is needed.